Studio A at Capitol Records in Hollywood is the fabled place where Frank Sinatra, Dean Martin, the Beach Boys and other stellar names in popular music made some of their most beloved recordings over the last half century.

On an unseasonably pleasant day last summer, however, the artist sitting dead center in front of the imposing 60-channel mixing board was Taylor Swift, the erstwhile teen queen of country-pop music who has dominated sales charts and captured the ears of her generation as firmly as any of her celebrated predecessors.

To Swift's right is Nathan Chapman, the producer she worked with on her multiplatinum 2006 debut album, "Taylor Swift," and its even bigger-selling 2008 follow-up, "Fearless," albums that have sold nearly 11 million copies combined.

On the other side of the glass partition separating the control booth from the studio, leading an orchestra of 28 string players, is Paul Buckmaster, the veteran British conductor-arranger whose string arrangements contributed substantially to the sound and success of Elton John's earliest records as well as more recent recordings by country star Tim McGraw and rock group Train.

It's the first time Swift has used an orchestra on record, and she sounds thrilled with what she's hearing as the violinists, violists and cellists bow edgy accents and dramatic countermelodies on two tracks — "Haunted" and "Back to December" — from her highly anticipated third album, "Speak Now," which will be released Monday worldwide.

"I couldn't sleep last night I was so freaked about this," Swift, 20, whispers nervously to a visitor seated next to her. "You should have seen me all geeky when I saw the names of the new songs on the sheet music out on their music stands. I was like, 'Oh my God, it's happening.'"

"Speak Now" represents a big musical step for Swift. It's one she's taking with a confidence that's made her a favorite of millions of teen girls as well as many of their parents, just as it's bred a legion of skeptics who argue that no one could remain so genuinely thrilled every time she or he steps in front of a TV camera.

Scott Borchetta, the veteran Nashville music executive who signed her at age 16 to his nascent Big Machine Records label, is impressed at how she's handled the success she's achieved in the last four years, becoming the biggest selling act in all of pop music.

Her debut album was a left-field hit many saw as a fluke. Then "Fearless" came out and proved Swift's appeal was anything but happenstance. Now, Borchetta recognizes the high expectations.

"We're not sneaking up on anyone with this one," he said. "For the first time in her career, we're not the underdog. All eyes are on her."

Case in point: the new album's first single, "Mine," leaked on the Internet ahead of its scheduled release date, kicking the campaign leading up to the album release into high gear early. It quickly rose to No. 3 on Billboard's Hot 100 singles chart and has sold more than 1.1 million digital tracks, pushing her total digital track sales above 30 million.

"In one breath, you could say everything is on the line," Borchetta said. "But when you really step back, it's just record No. 3, and this is not going to be her last record, whether it sells 5 million copies or a million and a half. That's for her fan base to decide."

Her own material

Back in the studio, Swift is wearing a light blue flower print miniskirt and a white top under a long, lightweight white sweater that dangles below the hem of the skirt. Her waist length brown hair is woven into a single braid that falls over her left shoulder, far enough into her lap that she often fiddles with it during the session with the orchestra.

The strings, however, aren't there simply to add musical sweetness; Swift and Chapman, who share production duties as they did on "Fearless," want them to add sonic bite and palpable emotion. The use of the orchestra is one indication of how Swift, pegged as the young singer and songwriter who created a niche for age-specific pop- country music and quickly came to own it, is growing up.

Another was her recent arena concert tour, a conceptually ambitious production that presented not just a cavalcade of her hits and album tracks to tens of thousands of fans each night, but a show that took them inside the head, heart and imagination of a typical teenage girl, warts and all. (She'll headline a world tour next year that's scheduled to include 85 shows in 18 countries.)

Where she'd worked on her first two albums with various writing partners, this time the songs are hers and hers alone — a source of pride for Swift, who views herself first and foremost as a songwriter.

"It was a great move for her," said John Ivey, program director for KIIS-FM (102.7), L.A.'s leading Top 40 station. "I can't tell you how many times on the last two records I heard people say 'She couldn't have possibly written this; it had to be the other writer.'"

She's won other fans in high places with her ability to tell stories that ring true.

"She blows me away," 74-year-old country music veteran Kris Kristofferson said backstage recently at Club Nokia, where Swift shared the stage with him and two other country standard bearers, Emmylou Harris and Vince Gill. "It's amazing to me that someone so young is writing such great songs," Kristofferson said. "She's got a great career ahead of her." Performing alongside Kristofferson put her on a plane with another songwriter who etched out a career more in spite of, than as a result of, his technical skills as a singer.

In December, Swift turns 21. The Wyomissing, Pa., native recently moved out of her parents' home in Hendersonville, Tenn., into a condo of her own near downtown Nashville that she's decorating herself, a step toward independence that her success is allowing her to take on a scale few of her fans can possibly relate to. She focuses instead on the emotional complexities of her transition on the new album in "Never Grow Up."

Swift quickly established a strong public persona as a typical teen wrestling with many of the issues her fans face. She's let them watch and listen in as she has navigated her way through life, first through the hyperdramatic waters of teenhood, and now into the onset of adulthood. She's tackling more sophisticated themes now than the ones that occupied her attention while she was just another high school student whose biggest worry was whether she'd have a date for the prom.

KIIS-FM's Ivey suggests Swift's transition from teen idol to adult pop star is developing far more organically than those of many other female singers who found fame early. He credits it to the songs she's written out of her own experience.

"She's different than poor Hilary, Miley, Christina or Britney," Ivey said. "Britney and, to some extent, Miley…. I love them both, but they had to go from being kids to humping a pole. It was a jerky A-to-B. This isn't."

In "Mine," Swift offers her side of dialogue with a boyfriend in which they wrestle with paying bills and their uncertainty over life and love. "Mean" is a biting and witty retort to critics who have skewered her singing ability, most vocally after her rocky duet with Stevie Nicks at the 2010 Grammy Awards. The ballad "Dear John" elucidates the hard choice of cutting ties with a love interest whom she discovers has "a sick need to give love and then take it away." She lets her inner brat show in the title track, which takes the theme of her hit "You Belong With Me" to the next level as she sings of interrupting the wedding of a beau she thinks is marrying the wrong girl.

Another example of her expanding choice of subject matter comes in "Innocent," which she introduced at the recent MTV Video Music Awards.

"This is a song I wrote about somebody who came into my life in the most freakish, unexpected, abrupt way," she told a visitor while listening to some rough mixes in a black Lincoln Navigator parked in the Capitol lot. In the song, she describes a person as "32 and still growing up/Who you are is not what you did/You're still an innocent." Writing the lyrics, says Swift, "taught me a lot about being able to step back from a situation you don't know what to do with, and put yourself in somebody else's shoes."

Kanye West, as it happens, was 32 at the time of last year's infamous VMA incident at in which he grabbed the microphone from Swift's hand after she'd won the award for best video. Was "Innocent" indeed her reaction to that situation? She answers obliquely.

"These songs are about different people in my life," she said. "Every song is about someone, and that person is going to know who they are." (Last week she acknowledged to Billboard that the song is about West.) The question remains whether writing songs about incidents that happen on national television will resonate with her fans like those about first loves and high school disappointments.

Music is No. 1

She's tried her hand at acting, with a guest appearance earlier this year on CBS' "CSI" series and a featured role in the romantic comedy "Valentine's Day." But Swift's priority remains her music, even as she's evolved from a kid who started knocking on record company doors in Nashville at age 11 to a certified country-pop star to a merchandising brand that has included a line of inexpensive sundresses she designed for Wal-Mart, a series of American Greetings cards she designed and wrote, and a soon-to-be-introduced line of luxury cosmetics for CoverGirl.

"When we get into a room to make music, it's pretty much like the first day we worked together," producer Chapman said in a separate interview. "As far as her writing and her art, she's just been getting better and better.

"She's got the [songwriting] craft down," he said. "She's constantly editing the lyric as we're working on the song, trying to make every line feel right. She'll write herself into a corner, then write herself out pretty quickly. It's pretty fascinating to be around her when she's in that mode."

"She's still the same Taylor I met when we first started working together," Chapman added. "If I haven't seen her change as a person, then she's handling this massive success pretty well."